U.S. patent application number 16/500917 was filed with the patent office on 2020-04-16 for electrically insulated electric conductor strip, in particular for electric motors and transformers.
This patent application is currently assigned to ALANOD GMBH & CO. KG. The applicant listed for this patent is ALANOD GMBH & CO. KG ALCOTEC ALUMINIUM COIL TECHNOLOGY GMBH. Invention is credited to MARCUS WALDER, VOLKER WANDELT, STEFAN ZIEGLER.
Application Number | 20200118707 16/500917 |
Document ID | / |
Family ID | 61899173 |
Filed Date | 2020-04-16 |
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United States Patent
Application |
20200118707 |
Kind Code |
A1 |
WALDER; MARCUS ; et
al. |
April 16, 2020 |
ELECTRICALLY INSULATED ELECTRIC CONDUCTOR STRIP, IN PARTICULAR FOR
ELECTRIC MOTORS AND TRANSFORMERS
Abstract
An electrically insulated electrical conductive strip (1),
especially for electric motors and transformers, having an
electrical conductor (2) in strip form that has an upper face (2a)
and a lower face (2b), two lateral edge faces (2c) and one end edge
face at each end, and having an electrical insulation (3) disposed
on at least one face of the strip (2a, 2b). The insulation (3) has
an enamel layer (3a) and an adhesive strip (3b) bonded to the lower
face (2b) and/or the upper face (2a) of the electrical conductor
(2) in strip form, in each case at least in a region (4) that
directly adjoins a lateral edge face (2c).
Inventors: |
WALDER; MARCUS;
(WIPPERFURTH, DE) ; ZIEGLER; STEFAN; (SPROCKHOVEL,
DE) ; WANDELT; VOLKER; (KOLN, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ALANOD GMBH & CO. KG
ALCOTEC ALUMINIUM COIL TECHNOLOGY GMBH |
ENNEPETAL
ENNEPETAL |
|
DE
DE |
|
|
Assignee: |
ALANOD GMBH & CO. KG
ENNEPETAL
DE
ALCOTEC ALUMINIUM COIL TECHNOLOGY GMBH
ENNEPETAL
DE
|
Family ID: |
61899173 |
Appl. No.: |
16/500917 |
Filed: |
March 19, 2018 |
PCT Filed: |
March 19, 2018 |
PCT NO: |
PCT/EP2018/056831 |
371 Date: |
October 4, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F 27/25 20130101;
H01F 41/0213 20130101; H01F 27/2847 20130101; H01B 7/0018
20130101 |
International
Class: |
H01B 7/00 20060101
H01B007/00; H01F 27/28 20060101 H01F027/28 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 5, 2017 |
DE |
10 2017 107 328.0 |
Claims
1. An electrically insulated electrical conductive strip, adapted
for use in machines and devices including electric motors and
transformers comprising, an electrical conductor in a strip form
that has an upper face and a lower face, two lateral edge faces and
one end edge face at each end, and an electrical insulation
disposed on at least one of the faces of the strip, the insulation
comprises an enamel layer and an adhesive strip bonded to the lower
face or the upper face of the electrical conductor in a strip form,
at least in a region of the upper or lower face that directly
adjoins one of the lateral edge faces.
2. The conductive strip according to claim 1 further comprising,
the adhesive strip is bonded in a C shape around one of the lateral
edge faces proceeding from the upper and the lower faces.
3. The conductive strip according to claim 1 further comprising,
the adhesive strip has an excess with respect to one of the lateral
edge faces of the electrical conductor in strip form having a
length in the range of 0 cm to 5 cm.
4. The conductive strip according to claim 1 further comprising,
the electrical conductor in strip form consists of aluminium or of
an aluminium alloy and has a thickness in the range from 0.1 mm to
1.5 mm.
5. The conductive strip according to claim 1 further comprising,
the enamel layer is formed above or beneath the adhesive strip.
6. The conductive strip according to claim 1 further comprising,
the enamel layer has a thickness in the range from 5 .mu.m to 50
.mu.m.
7. The conductive strip according to claim 1 further comprising,
the adhesive strip has a thickness in the range from 3 .mu.m to 20
.mu.m, and the thickness is at least half the thickness of the
enamel layer in a region where there is no adhesive strip.
8. The conductive strip according to claim 1 further comprising,
the enamel layer is formed from at least one of, an enamel based on
an organic polymer, an acrylic enamel, an epoxy enamel, a polyester
enamel, a polyimide enamel, a fluoropolymer enamel, or a sol-gel
composition, and a THEIC-modified polyesterimide.
9. The conductive strip according to claim 1 further comprising, a
region of the adhesive strip directly adjacent to one of the
lateral edge faces of the electrical conductor in strip form has a
width in the range from 0.2 cm to 4.5 cm.
10. The conductive strip according to claim 1 further comprising, a
region of the adhesive strip directly adjacent to one of the
lateral edge faces of the electrical conductor in strip form has a
width in the range from 0.5 to 1.5 cm.
11. The conductive strip according to claim 1 further comprising,
the insulation is disposed on both the upper and the lower face.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a 35 U.S.C. .sctn. 371 national phase of
PCT International Application No. PCT/EP2018/056831, filed Mar. 19,
2018, which claims the benefit of priority under 35 U.S.C. .sctn.
119 to German Patent Application No. 10 2017 107 328.0, filed Apr.
5, 2017, the contents of which are incorporated herein by reference
in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to an electrically insulated
electrical conductive strip, especially for electric motors and
transformers, having an electrical conductor in strip form that has
an upper face and a lower face, two lateral edge faces and one end
edge face at each end, and having an electrical insulation disposed
on at least one face of the strip.
BACKGROUND
[0003] Such electrical conductive strips are referred to, for
example, as electrical sheet or electrical strip and are used to
establish magnetic circuits for electrical machines, i.e. of cores
for dynamos, electric motors, transformers, relays, circuit
breakers, inductor coils, ignition coils, electricity meters and
controllable deflecting magnets. Customary materials here are
especially cold-rolled strips and sheets of iron-silicon alloys.
Since eddy currents arise under the influence of variable magnetic
fields in a coil core made of solid material, which can cause the
core to become hot, the cores are executed exclusively as laminar
and insulated sheets in stacks or in the form of wound cut-ribbon
cores.
[0004] In order to achieve insulation between two mutually
superposed conductive strip plies, plastic plies are nowadays used,
for example, as insulation in metal strip coils. Polyimide films
are often used for this purpose, which are sold, for example, by
DuPont under the Kapton.RTM. name.
[0005] In order to reduce the cost and inconvenience involved in
the production of a metal strip coil, an alternative to the laying
of films between the strips would be to coat the strip with an
electrical insulation enamel on one or both sides, as is known to
be implemented with conductors having a round cross section. For
this purpose, there are known wire enamels that are synthetic
resin-based insulating enamels, which can be applied as very thin,
homogeneous, electrically insulating films to copper or aluminium
wires. A distinction is made here between different groups of wire
enamels, such as THEIC-modified polyesterimides, polyamides and
epoxides, solderable wire enamels composed of polyurethane, and
adhesive enamels, for example composed of PVB (polyvinylbutyral)
and polyimide.
[0006] In the enamel coating of an electrical conductive strip of
rectangular cross section that can be described as cuboidal in
geometric terms and hence has an upper and lower face, two lateral
edge faces and one end edge face at each end, however, especially
the two lateral edge faces in that case regularly remain
insufficiently coated or even completely uncoated. This is because,
before the actual polymerization, effected, for example, by what is
called a baking operation of the wire enamel, owing to the surface
tensions, a meniscus forms, as a result of which the enamel layer
then narrows to a minimum or even forms defects during the enamel
hardening at the respective upper and lower edge of the lateral
edge faces where these each adjoin the faces. The electrical
insulating effect is then inadequate here. There can be flashovers
between the plies and/or at least formation of stray currents.
[0007] It is an object of the present invention to provide an
electrically insulated electrical conductive strip of the type
specified at the outset, which is producible at reduced cost and
inconvenience, especially using a varnish for the insulation, but
has a high electrical insulation effect.
SUMMARY
[0008] The above object is achieved in accordance with the
invention in that the insulation comprises an enamel layer and a
film adhesive strip bonded to the lower face and/or the upper face
of the electrical conductor in strip form at least, in each case in
a region that directly adjoins a lateral edge face.
[0009] The strip edge, especially before (or alternatively after)
the enamel coating, is laminated with a thermally stable adhesive
strip (for example of polyimide). Thus, by comparison with the
prior art, it is possible to replace a large area of the costly
plastic ply with enamel without impairing the electrical insulation
effect at the strip edge.
[0010] Further advantageous executions of the invention are
described in the detailed description that follows.
DESCRIPTION OF THE DRAWINGS
[0011] The invention is elucidated in detail by an example
illustrated by the appended drawing.
[0012] FIG. 1 shows, in a schematic diagram, a conductive strip of
the invention.
[0013] FIGS. 2 to 7 show variants of the conductive strip of the
invention.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0014] With regard to the description that follows, it is
explicitly emphasized that the invention is not limited to the
example, nor is it limited to all or multiple features of
combinations of features described. Instead, any individual
component feature of the example may be of inventive significance
on its own, and also in combination with other component features,
even in isolation from all other component features described in
connection therewith. FIGS. 2 to 7 identify identical parts of the
conductive strip by the same reference numerals.
[0015] The inventive conductive strip 1 shown in FIG. 1 comprises
an electrical conductor 2 in strip form that has an upper face 2a
and a lower face 2b, two lateral edge faces 2c and an end edge face
at each end (not shown). In addition, the inventive conductive
strip 1 comprises an electrical insulation 3 applied on at least
one side of the strip 1; in the embodiment shown, both to the lower
face 2b and to the upper face 2a.
[0016] The insulation comprises an enamel layer 3a and an adhesive
strip 3b, especially a film adhesive strip, consisting of plastic
and bonded to the lower face 2b and/or the upper face 2a of the
electrical conductor 2 in strip form, in each case at least in a
region 4 directly adjoining a lateral edge face 2c.
[0017] The adhesive strip 3b has an excess 5 with respect to the
lateral edge face 2c of the electrical conductor 1 in strip form,
which can prevent stray currents. The excess 5 may preferably have
a length L in the range of 0 cm<L.ltoreq.5 cm.
[0018] The electrical conductor 2 in strip form may especially
consist of aluminium or of an aluminium alloy and preferably have a
thickness D in the range from 0.1 mm to 1.5 mm.
[0019] The enamel of the enamel layer 3a, which can be applied by
dipping, as by electrocoating, or by brush application, roll
application, spin-coating, spraying, especially in a continuous
belt method, and then cured, has the effect that at least the lower
face 2b and/or the upper face 2a has adequate electrical
insulation.
[0020] The enamel layer 3a may be formed here from an enamel based
on organic polymers, as of an acrylic enamel, epoxy enamel,
polyester enamel, polyamide enamel or fluoropolymer enamel, or be
based on sol-gel compositions, especially of a wire enamel such as
a THEIC-modified polyesterimide. It may preferably have a thickness
DL in the range from 5 .mu.m to 50 .mu.m. As stated, in the region
of the adhesive strip 3b, this thickness DL may also be smaller,
especially in order to give rise to a flat surface O of the
insulation 3.
[0021] The adhesive strip 3b may preferably have a thickness DK in
the range from 3 .mu.m to 20 .mu.m, where this thickness DK may
preferably be at least half the thickness DL of the enamel layer 3a
in the region where there is no adhesive strip 3b.
[0022] The region 4 directly adjoining the lateral edge face 2c of
the electrical conductor 2 in strip form may have a width B in the
range from 0.2 cm to 4.5 cm, preferably in the range from 0.5 to
1.5 cm.
[0023] FIGS. 2 to 7 show further embodiments.
[0024] In FIG. 2, the two excesses 5 of the adhesive strips 3a, 3b
applied at either end are bonded to one another by a glue.
[0025] In FIG. 3, the adhesive strip 3b has been applied with the
excess 5 only at one end, and the enamel layer 3a tapers like a
meniscus on the adhesive strip 3b and ends before the excess 5. In
this case, the lower face 2b and the respectively adjoining lateral
edge face 2c has been provided with the enamel layer 3a, where the
enamel layer 3a at the transition to the lateral edge face 2c and
thereon may have such a thickness DL that, in itself, is
insufficient for the required electrical insulation.
[0026] FIG. 4 shows an alternative to FIG. 3, in which the face 2b
and lateral edge face 2c each have no electrical insulation and
especially no enamel layer 3a.
[0027] FIG. 5 shows a variant in which the adhesive strip 3b is
bonded in a C shape around the lateral edge face 2c proceeding from
the two faces 2a, 2b by a cover section 3c. In this execution too,
the enamel layer 3a ends like a meniscus on the adhesive strip 3a
before commencement of the cover section 3c.
[0028] FIG. 6 shows an alternative to FIG. 3. In this case, the
enamel layer 3a has been applied only on one side of the upper face
2a and on the adhesive strip 3b up to the start of the cover
section 3c.
[0029] FIG. 7 shows a variant of FIG. 5. Here, the electrical
conductor 2, in the region of its lateral edge face 2c, has a
reduced strip thickness Di compared to the strip thickness D in the
rest of the strip region. In this case, in particular, the
reduction in strip thickness in the region of the faces 2a, 2b is
the same and is less than/equal to the thickness DK of the adhesive
strip 3b. The enamel layer 3a runs here continuously up to the
cover section 3c.
[0030] The person skilled in the art is also able to add further
technical features without leaving the scope of the invention. For
instance, the working example shows just one option for the
lamination with the adhesive strip 3b. Alternatively, it is also
possible to lay an adhesive strip 3b around the edge area 2c, or
the enamel layer 3a could be beneath the adhesive strip 3b.
[0031] While the above description constitutes the preferred
embodiment of the present invention, it will be appreciated that
the invention is susceptible to modification, variation and change
without departing from the proper scope and fair meaning of the
accompanying claims.
* * * * *